Cooling assembly

ABSTRACT

A process and the required apparatus for air conditioning the interior of a structure is shown which can be run entirely off a DC power source, such as a storage battery. A shell and tube heat exchanger is combined with a mechanical refrigeration system to provide a wet shell side and a dry tube side of the apparatus. In the operation of the air conditioner, a mass of distributed water is established on the wet shell side, and a flow of ambient air is passed through the wet shell side to form a resulting stream of moist air. A flow of ambient air is passed through the dry tube side and a resulting stream of dry cooled air is recovered. The streams of most and cooled air can either be combined or routed separately depending primarily upon the humidity of the surrounding environment to be cooled. The air conditioning unit is not hermetically sealed and the water consumption rate is generally less than that required for a conventional evaporative cooler.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of my earlier filedapplication Ser. No. 10/629,121, filed Jul. 28, 2003, and which claimedthe benefit of U.S. Provisional Application No. 60/405,584, filed Aug.23, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to low power air conditioningsystems, and, in particular, to a low power air conditioning systememploying a tube and shell heat exchanger for use in arid conditions andto a combination direct/indirect evaporative cooler with refrigeratedsump water for use in other environments.

2. Description of the Prior Art

In one embodiment, the present invention provides air conditioning forstructures that are located in arid, high temperature environments, suchas deserts. Such environmental control is essential to enjoying a goodquality of life, and, in some instances, is essential to supportinglife. This is true for both humans and livestock.

In desert environments, daytime temperatures often reach well above 100degrees Fahrenheit while at the same time the relative humidity is oftenbelow 20 percent. Typically, conventional evaporative cooling based airconditioning systems, so called “swamp coolers”, are effective in suchconditions, because of the low humidity. A source of electrical power isrequired to operate such systems, so the cost of operation is alimitation on their use. Conventional evaporative coolers consumeconsiderable quantities of water so their use is limited to areas wherewater is available. Sufficient quantities of water are not alwaysavailable in desert environments. Other types of air conditioningsystems require sealed buildings, expensive and high maintenanceequipment, and are expensive to operate. Some dwellings and particularlybuildings in which livestock may be kept are not well sealed orinsulated so there is little impediment to the interiors of suchstructures reaching thermal equilibrium with the exterior environment.Typically, such structures are not provided with air conditioningsystems because of the cost of operating them and the generalineffectiveness of air conditioning systems in such structures. Most airconditioning systems operate on electricity, and electricity is notalways available, or is not available at a reasonable price where thestructures are located. It would be greatly beneficial to both humanbeings and livestock if an effective, simple, self-contained airconditioning system could be provided for desert environments that wouldoperate inexpensively in unsealed structures.

It would also be advantageous to provide an air conditioning systemwhich could be powered on direct current, either by batteries or solarpanels, or both, which system had the previously described advantageswhile at the same time being operable over wider humidity rangesincluding tropical and semi-tropical climates.

It would be a further advantage to provide such a system which utilizedboth a relatively wet airstream and a relatively dry airstream, whichairstreams could be selectively routed to the interior of a structure tobe cooled, either by combining the streams in a predetermined ratio orby selecting, for example, only the relatively dry airstream to bedelivered to the space to be cooled in the presence of high humidity.

In its simplest form evaporative cooling of buildings has beenaccomplished by injecting a fog or mist of water into a moving stream ofair. See, for example, Atkins, U.S. Pat. No. 5,146,762. One problem withthis system is that it causes excess humidity within the buildingresulting in algae and bacteria problems. Atkins proposes to minimizesome of these problems by placing exhaust fans at one end of a buildingwidely spaced from fogger nozzles at the opposite end of the building.The disclosed rate of water consumption is very high. In excess of 95percent of the water supplied to the fogger nozzles is consumed. Atkins'evaporative cooling system is said to produce a temperature drop ofapproximately 20 degrees.

Conventional evaporative cooling systems have been combined into moreelaborate systems that include heating means. See, for example, Grant etal. U.S. Pat. No. 4,773,471. Conventional evaporative cooling systemshave also been combined into elaborate systems with refrigerated airsystems. See, for example, Conner U.S. Pat. No. 5,911,745.

Urch U.S. Pat. No. 6,434,963 discloses an air cooler with two air flowpaths, namely, an inlet path for outside air and an outlet path forstale air. A heat exchanger pre-cools the fresh air with heat extractedfrom the stale air, and further cooling is achieved by means of anevaporative cooler that spans the two air flow paths.

Those concerned with these problems recognize the need for an improvedair conditioning system.

SUMMARY OF THE INVENTION

In one embodiment, the air conditioning assembly according to thepresent invention comprises a shell and tube heat exchanger whereinambient air is forced through both sides and discharged approximatelytogether into the interior of the structure that is to be cooled. Forconvenience, the air streams from the two sides can be combined into onecombined stream before being discharged into the interior of thestructure, or they may be discharged separately into the structure. Thisheat exchanger is particularly suited for use in the high heat and lowhumidity conditions that are typically found during the summer months indeserts. The air conditioning assembly is particularly effective insituations where the temperature is above approximately 80 degreesFahrenheit, and the relative humidity is below approximately 40 percent,and, preferably, below approximately 35 percent. The assembly issuitably operable even in situations where the structure to be airconditioned is not tightly sealed, that is where there may be openingsthrough the structure that are substantially unobstructed to air flowhaving as much as, for example, six square inches to a square foot ortwo of area. Barns, tents, temporary structures and the like areprovided with an efficient, reliable, economical, simple, and effectiveair conditioning system according to the present invention. The airconditioning system according to the present invention does not requirean elaborate or expensive installation for its functioning. It can beeasily transported to and set up inside of a temporary structure suchas, for example, a tent.

The shell side of the heat exchanger is preferably wet with a shower orweep of a liquid such as water, and the air flow is turbulent throughthe shell side. The stream of flowing air is directed from the shellside to an outlet. The air flowing through the tube side is cooled bycontact with the walls of the tubes, and is discharged to an outlet.Preferably the air streams from the shell and tube sides are combinedand discharged into the interior of the structure that is to be cooled.These air streams can be combined after discharge into the interior ofthe structure, if desired. Preferably, the intake and discharge of theair streams are all within the interior of the structure.

In another embodiment, the present invention comprises a direct/indirectevaporative cooler with refrigerated chilled sump water. The cooler ispreferably designed as a stacked arrangement. A refrigeration compressorand storage batteries occupy a top section of the design and rest on atop shelf. The top shelf forms the top wall of an exhaust air plenum. Aforced-air evaporative cooling chamber, located below the exhaust airplenum, occupies the middle section of the design and comprises about65% of the total height of the unit in one embodiment. A cold water sumpand an intake air plenum occupy the bottom floor of the cooling chamber.The bottom floor of the cooling chamber also comprises the top wall ofan intake plenum which houses an intake fan. The intake fan draws airupwardly through a plurality of riser tubes which connect the intakeplenum with the exhaust plenum and which pass through the coolingchamber.

Water in the cold water sump is refrigerated by the refrigerationcompressor located in the top section of the design. Cold water from thecold water sump is introduced into the evaporative cooling chamberthrough a distribution header. The cold water saturates an evaporativemedia which surrounds or otherwise contacts the riser tubes in thecooling chamber. Air is introduced into the cooling chamber by means ofoppositely arranged fans mounted on sidewalls of the cooling chamberwhich create a turbulent air flow in the cooling chamber and whichenhance the evaporative cooling process. Cooled air from the coolingchamber can be discharged through a suitable duct to the interior of thestructure to be cooled.

Air is also being drawn into the intake plenum by the intake fan, whichair flow is forced upwardly through the riser tubes in the coolingchamber. The riser tubes pass though the cold water sump and alsocontact the evaporative media in the cooling chamber, whereby theoutside of the tubes are cooled. The air within the tubes is cooled byconduction through the tubes. This relatively drier air can be directedthrough a suitable duct to the interior of the structure to be cooledand can be combined with the more moist, cooled air from the coolingchamber, if desired.

In this latter embodiment of the invention, air is being cooled usingtwo simultaneous processes. Air is cooled by direct contact with waterin the evaporative cooling chamber, raising the absolute humidity of theair cooled in this manner. Additional air is also being cooled byconductive heat transfer within the riser tubes. The absolute humidityof this additional air is either unchanged or only slightly changed, ordecreases slightly, due to condensation on the inside of the risertubes. If desired, the two air flows can be combined into a dischargeduct so that the discharged air consists of a mixture of relativelyhumid air from the evaporative process and air with near ambienthumidity. Control over the humidity of the discharged air can beobtained by regulating the ratio of the two previously described airflows.

The cold water sump at the bottom of the cooling chamber serves as acooling mass, as well as a water storage sump. The water in the sump isrefrigerated to near freezing by means of a low temperature compressorsimilar to that used on an ice machine. The compressor can be AC or DCoperated, but is preferably DC operated. The electric fans used in theintake plenum and on the cooling chamber are preferably DC fans whichcan be driven by solar cells or storage batteries.

Other objects, advantages, and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention provides its benefits across a broad spectrum ofstructures. While the description which follows hereinafter is meant tobe representative of a number of such applications, it is notexhaustive. As those skilled in the art will recognize, the basicmethods and apparatus taught herein can be readily adapted to many uses.It is applicant's intent that this specification and the claims appendedhereto be accorded a breadth in keeping with the scope and spirit of theinvention being disclosed despite what might appear to be limitinglanguage imposed by the requirements of referring to the specificexamples disclosed.

Referring particularly to the drawings for the purposes of illustrationonly and not limitation:

FIG. 1 is a diagrammatic view of one embodiment of a tube and shell heatexchanger according to the present invention.

FIG. 2 is a cross-sectional view taken along line 2-2 In FIG. 1.

FIG. 3 is a diagrammatic cross-sectional view taken through the shellplenum of a further embodiment according to the present inventionshowing a liquid spray system.

FIG. 4 is a diagrammatic cross-sectional view taken through the shellplenum of a further embodiment according to the present inventionshowing the tubes fully enclosed in blankets.

FIG. 5 is a plan view of a structure in which a tube and shell heatexchanger air conditioning system according to the present invention hasbeen installed.

FIG. 6 is a cross-sectional view of the heat exchanger of FIG. 5 takenthrough the shell plenum.

FIG. 7 is a chart of the temperature and relative humidity readingsrecorded in Tables 4 and 5 at locations 116 and 120 in FIG. 5.

FIG. 8 is a perspective view of another embodiment of the device of theinvention which features combined direct/indirect evaporative coolingwith refrigerated chilled sump water.

FIG. 9 is a rear view of the device of FIG. 8 with the rear wall removedfor ease of illustration of the internal components of the device.

FIG. 10 is an isolated view of the cooling chamber and refrigerationmanifold used in the device of FIGS. 8 and 9.

FIG. 11 is a perspective view of the device of FIG. 8 with the rear wallremoved for ease of illustration of the internal components of thedevice.

FIG. 12 is a view of the top wall of the cooling chamber which alsoserves as a tube sheet for the riser tubes.

FIG. 13 is an isolated view of the cooling chamber of the device of FIG.8.

FIG. 14 is a side view of the cooling chamber showing the location ofthe water distribution array.

FIG. 15 is an isolated view of the air intake plenum and air intake fan.

FIG. 16 is an isolated view of the refrigeration manifold used in thecold water sump of the device of FIG. 8.

FIG. 16A is a cross sectional view taken along lines 16A-16A in FIG. 16.

FIG. 16B is a simplified end view of the manifold of FIG. 8 showing thecross-over piping arrangement used to produce the interlayered flowpattern.

FIG. 17 is a simplified, schematic view of an auxiliary heat exchangeunit which can be operated off the chilled water in the cold water sumpof the device of the invention.

FIG. 18 is a cross-sectional view of a cable used to connect theauxiliary heat exchange unit of FIG. 17 with the main cooling assemblyshown in FIGS. 8-15.

DETAILED DESCRIPTION OF THE INVENTION

The detailed description of the invention will now be provided withrespect to two different preferred embodiments:

Low Humidity Air Conditioner Embodiment:

Referring now to the drawings wherein like reference numerals designateidentical or corresponding parts throughout the several views, there isillustrated generally at 10 a tube and shell heat exchanger, which isparticularly adapted for use as a low power air conditioning unit inhigh temperature, low humidity conditions with structures that are nothermetically sealed. The floor plan of such a structure is indicatedgenerally at 64 in FIG. 5.

Heat exchanger 10 is confined within external case 62. For purposes ofillustration, external case 62 is shown as rectangular, but otherarcuate, spherical, or cylindrical forms are contemplated within thescope of the present invention.

Air, preferably internal air from near the ceiling of a structure thatis to be cooled, is drawn into the tube side of the heat exchangerthrough inlet port 12 into intake plenum 14 of heat exchanger 10. Air isdrawn into inlet port 12 by exhaust fan 46. Air is drawn from intakeplenum 14 through heat exchange tubes 34 into exhaust plenum 18. Tubeinlet ends 36 are sealingly mounted in inlet tube sheet 60, and tubeoutlet ends 38 are sealingly mounted in tube outlet sheet 32. Exhaustfan 46 expels the air from the tube side of the heat exchanger into tubeside exhaust conduit 22.

The shell side of heat exchanger 10 is in the form of a shell plenum 16that surrounds heat exchange tubes 34 between inlet tube sheet 60 andoutlet tube sheet 32. Heat exchange tubes 34 are shown for the purposesof clarity of illustration as being straight, but, as will be understoodby those skilled in the art, other forms such as coiled or looped heatexchange tubes can be used. A body of liquid, preferably water, isdisposed within the shell side of heat exchanger 10. The surface of thebody of liquid is indicated at 50. The liquid generally occupies lessthan one-half, and preferably, less than one-quarter of the volume ofthe shell side of the heat exchanger. The bottom portion of the shellplenum 16 forms a liquid sump in which the liquid resides. At least one,and preferably at least two fans are position to force ambient internalair from within the structure into shell plenum 16 of heat exchanger 10.In FIG. 1, three such shell side input fans are indicated at 40 (firstinput fan), 42 (second input fan), and 44 (third input fan). These fanstogether generate substantial turbulence in the air on the shell side ofheat exchanger 10. The air from shell plenum 16 is expelled from heatexchanger 10 through shell side exhaust conduit 20.

The liquid in the sump within shell plenum 16 is sprayed over the heatexchange tubes 34. One form of a spray system is illustrated in FIG. 1,and consists of a pump feed line 26 that serves to convey liquid fromthe liquid sump on the shell side to liquid pump 24. Pump 24 suppliesenergy to the liquid and discharges it through pump discharge line 28 tospray head 30 where it is sprayed over the shell sides of heat exchangetubes 34. Spray head 30 is typically located at or near the top of theshell side plenum, although this is not necessary to the operation ofthe system. It is schematically illustrated here on the side of theshell side plenum for ease of illustration. The liquid runs and fallsback down into the sump where it is recycled again. The liquid sprayenhances the heat transfer between the heat exchange tubes 34 and theliquid, as well as rapidly increasing the humidity of the air in theshell plenum 16. Preferably, the liquid level is automaticallymaintained at about a constant level by means of a conventional floatactuated valve connected to a supply of liquid (not shown).

Heat transfer between the liquid and the heat exchange tubes 34 isfurther enhanced by the provision of blanketing members, for example,tubular foam blankets 48 (FIG. 4), or loose reticulated foam sheets 104(FIG. 6) positioned in physical contact with the heat exchange tubes 34.Also, the humidification of the air in shell plenum 16 is enhanced bythe presence of blanketing members of some form. The blanketing membershold the liquid against the heat exchange tubes 34, and increase thesurface area of the liquid within shell plenum 16. In general theblanketing members comprise inert reticulated material through whichliquid and vapor phase liquids flow easily. Numerous such reticulatedmaterials are known, including, for example, many natural and syntheticopen pore foams, felts, battings, woven materials, and the like.Conventional commercial swamp cooler pads are generally suitable for useas the blanketing elements. Often such materials include bacteria stats,fungi stats, and the like. The blanketing materials can completely orpartially enclose heat exchange tubes 34, as desired. Compare, forexample, FIGS. 4 and 6. For the sake of clarity of illustration, theseblanketing members are not illustrated in FIGS. 1, 2, and 3, but theyare preferably employed in some form.

Various liquid spray systems can be employed. A particularly effectivesystem is illustrated particularly in FIG. 3. Liquid from a suitablesource such as, for example, the sump in shell plenum 16, is suppliedunder pressure to spray header 52 and distributed to spray headerbranches 56. Liquid is expelled in a shower from spray ports 54.Preferably, spray header 52 is positioned at the normally upper end ofshell plenum 16 adjacent to outlet tube sheet 32 so that liquid showersdown over the heat exchange tubes 34 and any associated blanketmaterial, and is acted upon by the turbulent air flow from the shellside fans 40, 42, and 44.

The air exhausted from the tube side through exhaust conduit 22 ispreferably mixed with the air exhausted from the shell side throughexhaust conduit 20. The combined air streams are discharged to theambient interior of the structure that is being cooled through combinedexhaust conduit 58.

The best mode for the first embodiment of the invention presentlycontemplated is illustrated particularly by reference to FIGS. 5 and 6.An unfinished barn indicated generally at 64 has a rectangular shapeabout 30 feet wide and 50 feet long. Barn 64 is oriented east to westalong its long axis as indicated by the letters N, S, E, W, in FIG. 5.Barn 64 has an uninsulated peaked metal roof, exposed 2 by 4 wooden studwalls, and a stucco exterior finish. The peak of the roof is about 10feet from the floor, and the exterior walls are about 8 feet high. Theinterior volume of barn 64 is approximately 13,500 cubic feet. Theexterior doors are not weather sealed and the total unsealed area aroundthe exterior doors 66, 68, 70, 72, and 74 combined is from approximately1 to 2 square feet. No significant pressure differential exists betweenthe interior of barn 64 and the external environment, and any moisturecontent differential between the interior of barn 64 and the ambientenvironment tends rapidly towards equilibrium. Stall partitions 82, 84,86, and 88 are half height, and stall dividers 80 and 78 are full heightextending to within approximately 6 inches of the roof. Interior gate 76is a full height security screen door.

The air conditioning system employed in barn 64 consists of tube andshell heat exchanger 10, combined exhaust conduit 58, air distributionchamber 92, air distribution branches 94 and 96, and air outlet heads 98and 100. Input fans 42 and 44 supply ambient air from the interior ofbarn 64 to the shell plenum in heat exchanger 10. The air is typicallydrawn into the shell side of the heat exchanger from a level well belowthe level at which air is discharged at 98 and 100. Air is preferablydrawn into the tube side of the heat exchanger from the hottest part ofthe structure adjacent to the uninsulated roof. Air exhausted from thetube side of heat exchanger 10 through tube side exhaust conduit 22mixes with air exhausted from the shell side through conduit 20, andflows through combined exhaust conduit 58 to air distribution chamber92. The air stream then splits and flows through each of airdistribution branches 94 and 96 to respective air outlet heads 98 and100. Air is drawn into the tube side of heat exchanger 10 through inletport 12. Blanket material 104 (FIG. 6) in the form of conventional swampcooler foam pads is in contact with tubes 34. A spray head of thegeneral configuration shown in FIG. 3 positioned in the top of the shellplenum of heat exchanger 10. Preferably, approximately the lowerone-quarter of the shell plenum is filled with water.

The rectangular exterior case of heat exchanger 10 is approximately 3feet high by 2 feet by 2 feet, and it rests on the floor of barn 64.Input fans 42 and 44, mounted on opposed sides of the case, are 14inches in diameter, run at 2,200 revolutions per minute, and operate on12 volts of direct current. The rated amperage of these fans is 4 amps.The tube side exhaust fan 46 (FIG. 1) is a 12 inch, 12 volt, directcurrent, 4 amp fan. These fans are conventional automotive equipment,and they are typically used in association with conventional radiatorcooling systems to pull air through the radiator of a liquid cooledinternal combustion engine. The liquid pump 24 (FIG. 1) has a 12 volt, 7amp, direct current motor, and a rated flow rate of 28 gallons per hour.The dimensions of the tube side intake plenum 14 (FIG. 1) are about 6inches high by 24 inches by 24 inches. The dimensions of the tube sideexhaust plenum 18 (FIG. 1) are about 6 inches by 24 inches by 24 inches.The dimensions of the shell side plenum 16 (FIG. 1) are about 24 by 24by 24 inches. The heat exchange tubes 34 are straight sections ofstandard three-quarter inch cylindrical copper tubing having a lengthbetween tube sheets 32 and 60 of about 24 inches. There are 100 heatexchange tubes 34 arrayed in a generally regularly spaced rectangularpattern. The total surface area of the tubes 34 within shell plenum 16is approximately 6,600 square inches. The intake port 12 for the tubeside of the heat exchanger has a diameter of about 6 inches as doconduits 20 and 22. Intake port 12 opens upwardly and is positionedapproximately 4 inches below the uninsulated metal roof of barn 64 so itis taking in approximately the hottest air within the interior of barn64. Combined exhaust conduit 58 runs overhead, as do air distributionbranches 94 and 96. The diameter of conduit 58 is about 8 inches, andconduit 58 is approximately 14 feet long. Each air distribution branchis approximately 10 feet long and 6 inches in diameter. The distributionbox 92 is approximately 2 by 2 by 2 feet. The short leg of conduit 58that runs into distribution box 92 is approximately 3 feet long. Airoutlet heads 98 and 100 discharge downwardly at a height ofapproximately 9 feet above the floor.

The pump and fans have, for example, direct current motors powered by 5conventional 12 volt deep cycle lead acid secondary batteries connectedin parallel, indicated generally at 106. The batteries are connectedthrough a conventional charging circuit indicated generally 108 to 3conventional 30 volt, 4 amp hour solar panels indicated generally at110, 112, and 114. The solar panels are mounted on the south facingpitch of the roof of barn 64. No other power source is required for thefull time daylight operation of the air conditioning system. If desired,a conventional AC converter could be used to charge the batteries off ofregular 110 volt house current, or some other power from a commercialutility service. This is not necessary, and would add to the cost ofoperation while limiting the system to use only at locations wherecommercial utility service is available. Likewise, the motors on thefans and pump could be replaced with conventional motors that wouldoperate on power from a commercial utility service, but the costs ofoperation would be increased, and the flexibility of the system would becompromised.

The level of water in the sump is preferably maintained at approximately5 inches. At this level the sump contains approximately 1.67 cubic feetof water. The shell side plenum has a volume of approximately 8 cubicfeet, so the water occupies approximately 21 percent of the volume ofthe shell side plenum 16. This provides an adequate reserve of water tocontinue operations for more than a day. Other sump volumes can be usedif desired, ranging from, for example, approximately 10 to 30 percent ofthe volume of the shell side plenum chamber 16. The sump need not bewithin the shell side plenum chamber. An external sump several timeslarger than the shell side plenum can be used if desired so as toprovide for at least a week of unattended operation without replenishingthe water supply. Less than a gallon of water is consumed during thecourse of the daylight hours in a typical summer day.

Barn 64 is located in a desert area where the daytime temperaturestypically exceed 100 degrees Fahrenheit for several months during thesummer, the relative humidity is often below 20 percent, and the sunshines for most of the daylight hours. Without air conditioning, thetemperature at mid-day within barn 64 usually exceeds the outsidetemperature by at least approximately 10 degrees Fahrenheit.

The operation of the air conditioning system in barn 64 can be automatedby providing a conventional thermostat (not shown) connected to the fansand pump circuits. Setting a thermostat at, for example, 74 degreesFahrenheit, will activate the system early in the morning on a typicalsummer day, and keep it running well into the evening hours.

A preferred air conditioning assembly according to the present inventionis fully self contained. That is, the power supply for the fan and pumpmotors is at the same location as the rest of the system. The watersupply on the shell side of the heat exchanger can be replenishedautomatically by a float actuated valve on a water line, or manually, asdesired. Where no reliable water supply is available, the rate of waterconsumption is so low that manual replenishment at widely spacedintervals is practical.

The power requirements are so small that a low voltage (12 or 24 volts)battery system coupled with a conventional solar panel driven chargingcircuit is sufficient to power the system during the daylight hours. Theconvenience of using a conventional solar panel charged battery system,and the widespread availability of such inexpensive systems, makespractical the unattended air conditioning of a wide variety ofstructures. Even livestock barns, for example, can be reliably andinexpensively air conditioned according to the present invention.Dwellings occupied by humans can likewise be air conditioned, even wherevery limited funds are available to devote to this purpose, and thedwellings are poorly sealed and uninsulated. The battery system can alsobe charged by wind turbines in areas where reliable wind flows areavailable. Other alternative energy sources can be used, if desired.Combinations of solar panels, wind turbines and other forms ofalternative energy are suitable for use in charging the battery system.Since alternative energy sources typically do not deliver a constantlevel of energy, and the motors employed in the system require asubstantially constant energy source, batteries are preferablyinterposed between the energy source and the air conditioning system.Where an alternative energy source is capable of delivering a constantsource of energy, the use of a battery system is optional.

The air conditioning system according to the present invention wasturned on in barn 64 at about 6:30 In the morning on a typical sunnysummer day, and allowed to run all day. The inside temperature of barn64 was measured at approximately location 102 (FIG. 5) approximately 4feet above the ground, and the exterior temperature was measured in theshade under an open awning adjacent to the south side of barn 64 atapproximately location 116. Location 116 is at a height of about 5 feetabove the ground on a support for a 20 foot wide awning (not shown). Thewooden awning is attached to the barn and extends outward from the levelof the top of the wall of the barn 64 for about 20 feet. The woodenawning is completely open on three sides, The temperature at 116 isapproximately what the temperature would be Inside of barn 64 withoutthe air conditioning system. The temperatures observed were as shown InTable 1 below. TABLE 1 Inside temperature Exterior temperature Time at1.02. in ° F. at 116, in ° F.  6:30 78 Not Recorded  7:30 72 NotRecorded  8:30 71 Not recorded  9:30 72  98 10:30 72  99 11:30 73 10512:30 75 104  1:30 75 100  2:30 77  98  3:30 76  98

It has been observed that the temperature difference between theinterior and exterior is the greatest when the humidity is the lowestand the outside temperatures are above 100 degrees Fahrenheit.

On a summer day when the sky was mostly overcast and the relativehumidity was above approximately 35 percent, the following conditionswere observed: TABLE 2 Outside temperature Interior temperature Time at116, in ° F. at 102, in ° F.  6:30 83 Not Recorded  9:30 85 75 10:30 9074 11:30 90 82 12:30 92 80  1:30 92 80  2:30 90 79  3:30 91 76

Relative humidity measurements were taken at various locations in andaround barn 64 on a sunny summer day commencing about 9:00 a.m.

The readings at the locations indicated by the listed reference numbersin FIG. 5 were recorded in Table 3. TABLE 3 Measurement Locations AsShown On FIG. 5 Time 98 100 78 116 44 42  9:00 30% 30% 31% 19% 31% 31%10:00 30% 30% 31% 18% 32% 32% 11:00 34% 34% 32% 18% 31% 30% 12:00 35%34% 34% 19% 30% 30%  1:00 37% 36% 35% 18% 32% 32%  2:00 34% 34% 35% 17%31% 31%  3:00 34% 34% 35% 16% 32% 32%  4:00 34% 34% 35% 16% 32% 32%

The relative humidity remains substantially stable and constantthroughout the day and throughout the interior of the structure.

Commencing about 9:00 a.m., Temperature and relative humiditymeasurements (T/H) were taken throughout a sunny day at variouslocations within and adjacent to barn 64. The readings were taken at thelocations indicated by the reference numbers in FIG. 5 and were recordedin Table 4. The measurements at locations 118 and 120 were taken about 5feet above the floor. Location 118 gives an indication of the effect ofradiation from the exterior wall. Location 124 is on the north side ofthe barn 64 about 5 feet above the ground. The measurements were asfollows: TABLE 4 Measurement Locations As Shown On FIG. 5 116 120 98 100Time T/H T/H T/H T/H 118 T 122 T 124 T  9:00  78/19   70/30 72.1/3070.8/30 69.6 64.1 85.5 10:00  82/18   73/30 75.1/30 76.4/30 72.1 65 85.711:00  90/18   75/27 77.9/34 79.3/34 75.2 65.2 90.5 12:00  94/19 79.9/3774.4/35 74.2/34 78.7 65.4 94.3  1:00 100/18 82.1/40 76.3/37 76.1/36 80.967.5 98.1  2:00 106/17 83.5/37 77.8/34 77.9/34 83.9 69.8 100.1  3:00116/16 83.1/37 79.2/34 79.4/34 87 71.9 107  4:00 118/16 85.7/34 80.6/3480.6/34 89.7 71.4 108  5:00 118/17   86/32 81.2/na 81.2/na 93 71.8 107.3 6:00 112/13   87/32 84.3/na 84.3/na 94.7 72.4 108

The temperature and relative humidity measurements as reported in Table4 were repeated under higher humidity conditions commencing about 10a.m. on a somewhat cloudy day. The system was activated by aconventional thermostat set at about 74 degrees Fahrenheit. The resultsare set forth in Table 5. TABLE 5 Measurement Locations As Shown On FIG.5 Time 116 T/H 120 T/H 98 T/H 100 T/H 118 T 122 T 124 T Volts 10:00  86/33 78.5/44 73.6/31 73.6/31 69.2 81 12 11:00   92/27   79/49 75.7/3275.7/32 74 68.4 88 11.6 12:00   92/23 79.5/47 76.7/31 77.1/31 75 69.3 8911.4  1:00   95/23 80.1/47 77.4/31 77.5/31 79 71.2 97 11  2:00   97/2080.2/45 79.6/33 79.9/32 79 74 98 9.4  3:00 98.3/20 83.0/ 81.6/34 81.7/3480 73.8 98 9.7 30**  4:00  106/20 84.1/41 81.6/34 81.9/34 92 74.5 99 9.6 5:00  110/22 84.1/42 82.1/34 82.2/31 94 74.2 101 9.1  6:00  110/25  85/43 82.8/35 82.8/35 94 74.4 101 10.3*  7:00  102/33   85/47 81.2/3581.7/35 91 74.2 100 10.0  8:00   96/42 83.1/47 80.1/35 79.2/35 90 73.696 11.1  9:00   84/42 80.1/47 76.3/36 77.1/36 89 72.5 81 12 10:00  77/44 78.1/47 74.1/34 74.7/34 87 71.1 77 12.5 11:00   75/44 76.1/4774.0/34 74.1/34 83 69.4 74 12.5 12:00   75/44 73.1/46 73.4/32 73.4/32 7967.1 74 12.5

A conventional 110 volt battery charger was connected to the nominal 12volt battery system at about 6 p.m. The effectiveness of the solarbattery charging system was diminished by occasional cloud cover duringthe day.This relative humidity reading is reported here as recorded, but,considered in light of the contemporaneous readings at locations 116,98, and 100, it is believed to reflect an operator or instrument error,and is not considered to be reliable. It is not reflected in relativehumidity curve 120-5 in FIG. 7.

The curves in FIG. 7 are based on the data recorded in Tables 4 and 5 atlocations 116 and 120 in FIG. 5. The relative humidity and temperaturecurves 116-4 in FIG. 7, for example, were drawn based on the data In thecolumn headed “116 T/H” in Table 4, and curves 116-5 were drawn based onthe data in the column headed “116 T/H” in Table 5. The last numberfollowing the dash indicates which Table the information for the curveis taken from.

A comparison of the temperature differences between temperature curves120-5 and 116-5 at various relative humidity readings, as shown byrelative humidity curve 116-5, indicates that the air conditioningsystem according to the first embodiment of the present invention ismost effective at exterior temperatures above approximately 90 degreesFahrenheit and relative humidity readings below approximately 40, andpreferably below approximately 35 percent. At exterior relative humidityconditions below approximately 20 percent, temperature differences of asmuch as approximately 35 degrees Fahrenheit were achieved. See, forexample, the differences between temperature curves 116-4 and 120-4 andrelative humidity curve 116-4 in FIG. 7. While the temperature in theopen shade reached almost 120 degrees Fahrenheit, the temperature inbarn 64 did not reach over about 87 degrees Fahrenheit. A temperature of120 degrees is life threatening while a temperature of 87 degrees isgenerally not. The efficiency of the system is best when the relativehumidity is below approximately 25 percent. See, for example, howtemperature curves 120-5 and 116-5 quickly converge once the relativehumidity exceeds approximately 35 percent, and actually cross atapproximately 45 percent relative humidity.

The last column in Table 5 reflects a drop in the voltage of the batterysystem during the hours of peak demand. This voltage drop is reflectedin a decrease in the volume of air that the various fans are able tomove through the system. Although Applicant does not wish to be bound byany theory, it appears that there is a small temperature rise(temperature curve 120-5, FIG. 7) that may be correlated with thereduced volume of air moving through the system between approximately 2p.m. and 6 p.m. The system appears to be relatively insensitive to smallchanges in the volume of air flowing through the system. Preferably, thevoltage should be at least approximately 11 volts for optimum operationof the fan motors. Adding another one or two solar panels to theexisting three panel array on the roof of barn 64 would provide enoughcapacity to hold this voltage during peak demand periods.

The column headed “122 T” in Table 5 indicates the exterior temperatureof the shell side of the heat exchanger. The water within the shell sideis typically approximately 10 to 15 degrees Fahrenheit cooler thanlocation 122. This affords the opportunity to provide some cooling toobjects placed in heat exchange relationship with this water. If accessis provided to the shell side, small objects can be cooled somewhatwithout the expenditure of significant additional amounts of energy. Theshelf life of small amounts of heat sensitive food stuffs or medicinescan be extended by placing them in heat exchanging relationship withthis water. Suitable containers can be placed directly in the water onthe shell side, or a cabinet accessible from the outside can be builtinto the shell side, or a stream of water circulated through, forexample, cooling coils external to the shell side, or the like, can beutilized to effect the cooling of objects.

The column headed “118 T” in Table 5 gives a rough indication of theheat that is being radiated into the interior of the structure by theexterior walls. The column headed “124 T” provides a rough indication ofthe effect of cooling the interior of barn 64 on the temperature of theexterior of the walls. Clearly, a significant amount of heat is beingtransferred through the uninsulated walls of barn 64. Location 116 isfar enough from the adjacent wall that there is very little if anyinfluence on the indicated temperature by reason of the cooling of theinterior of the barn 64. Comparison of columns 120, 98, and 100indicates that the temperature is relatively uniform throughout theinterior of barn 64.

It has been found that thermally insulating the case that encloses theheat exchanger improves the efficiency of the system by as much as 10percent or more. The temperature of the body of water on the shell sidetends to be reduced by the presence of the thermal insulation. Thedegree of thermal insulation is preferably such that the exteriortemperature of the shell side of the heat exchanger (Table 5, column122T) is at least 3, and preferably 5 degrees Fahrenheit warmer than theequivalent uninsulated metal exterior shell side temperature at anambient air temperature of approximately 80 degrees Fahrenheit. Changingfrom a metal case (18 gauge steel) to a fiberglass (glass filamentreinforced thermosetting resin) case with a thickness of approximatelyone-eighth inch reduces the temperature by approximately 5 degrees atabout 80 degrees Fahrenheit ambient internal air temperature. Theefficiency of the air conditioning system also increases. Numerous formsof insulation and methods of application are suitable for this purpose,as will be understood by those skilled in the art.

The rate of water consumption in an air conditioning, system accordingto the present invention is very low. For example, in the operation ofthe embodiment described herein with reference to FIG. 5 the rate ofwater consumption is no more than approximately 5 percent that of aconventional evaporative cooler (commonly described as a swamp cooler)operating under the same conditions. This low rate of water consumptionis achieved even though the structure or other confined space isuninsulated, and is so unsealed that it is free to leak substantialvolumes of air. In general, the rate of water consumption of a heatexchanger according to the present invention is less than approximately10 percent, and preferably less than approximately 5 percent that of aconventional direct evaporative cooler (in a conventional evaporativecooler a single stream of air passes through a moist environment and iscooled and humidified by the evaporation of water) operating undersubstantially the same conditions external to the cooling systems. Forcomparison's sake, substantially the same external conditions compriseabout the same exterior conditions of temperature and relative humidity,and the same structure or other confined space with, for example, thesame volume, shape, and insulation. For purposes of comparison, thedifferences in the results from the operation of the cooling system ofthis invention as compared to the operation of a conventionalevaporative cooler arises from the differences in the cooling systems,and not from the environment external to the coolers or thecharacteristics of the structure or other confined space. All of thevariables, other than those inherent in the two cooling systems, areheld constant for comparison purposes. That is, all of the externalvariables are held substantially constant. This low rate of waterconsumption is achieved while typically enjoying a humidifyingefficiency (dry-bulb temperature drop across the heat exchanger dividedby the maximum possible dry-bulb temperature drop as determined from aPsychometric chart) of from approximately 30 to 40 percent.

The relative humidity within the interior of an air conditionedstructure according to the first embodiment of the present invention issubstantially below that which would be expected from a conventionalevaporative cooler. Comparison of, for example, the data in columns “1161/H” and “120 T/H” in Tables 4 and 5 reveals that when the exteriorambient temperature exceeds approximately 95 degrees Fahrenheit, and theexterior ambient relative humidity falls below approximately 25 percent,the relative humidity within the structure is only approximately twice(200 percent) that in the exterior environment. As the exterior relativehumidity falls below approximately 20 percent, and the temperatureexceeds approximately 100 degrees Fahrenheit, the interior relativehumidity is generally greater than approximately twice that of theambient exterior environment, but still less than approximately 2.3times (230 percent) that of the ambient exterior environment. These lowinterior relative humidities of less than approximately 50 percent areobtained while maintaining the interior ambient temperatures belowapproximately 85 degrees Fahrenheit despite exterior temperatures ofapproximately 110 to 120 degrees Fahrenheit. Typical interior relativehumidities of less than approximately 60 percent are achieved accordingto the present invention whereas interior relative humidities in excessof approximately 60 percent are typically found with conventionalevaporative coolers operated under the same conditions. This minimizesthe growth of mold, and the like, as well as increasing the comfort ofthe occupants of the structure or other confined space. At these lowrelative humidities, temperatures of less than approximately 85 degreesFahrenheit are generally comfortable for most people. As will berecognized by those skilled in the art, achieving these conditions withunsealed, uninsulated structures, and with a very low rate of waterconsumption using only an ambient energy harvesting system such as, forexample, solar or wind energy, as described above, provides a veryeconomical air conditioning system that is highly desirable andbeneficial in many ways and for many purposes.

Variable Humidity Embodiment of the Invention:

Referring now to FIGS. 8-18, a variable humidity embodiment of theinvention will be described which can be used in high temperature, lowhumidity environments such as that previously described, but which canalso be used in higher humidity environments, including tropical orsemi-tropical environments.

With reference to FIG. 8, there is shown an air conditioner 201 which isa combined direct/indirect evaporative cooler with refrigerated chilledsump water. The variable humidity device 201 shown in FIG. 8 has anumber of common features with the low humidity device described withreference to FIGS. 1-7. The air conditioner 201 is preferably designedas a stacked arrangement having a top section 203, a middle section 205and a bottom section 207. A refrigeration compressor 209 and a storagebattery 211 (FIG. 9) occupy the top section 203 of the design and reston a top shelf 213. The top shelf 213 forms the top wall of an exhaustair plenum 215. A forced-air evaporative cooling chamber (217 in FIG. 9)is located below the exhaust air plenum and occupies the middle sectionof the design. The cooling chamber comprises a shell plenum for the airconditioner and comprises about 65% of the total height of the unit inthe particular embodiment illustrated in the drawings. A cold water sump219 is located in the bottom of the cooling chamber. The bottom floor223 of the cooling chamber 217 also comprises the top wall of an intakeplenum 221 housing an intake fan 225. The intake fan 225 draws airupwardly through a plurality of riser tubes 227 which connect the intakeplenum 221 with the exhaust plenum 215 and which pass through thecooling chamber 217.

As shown in FIGS. 10, 12 and 13, the bottom floor 223 of the coolingchamber has a plurality of openings 224 which form a lower tube sheetfor the riser tubes 227. Similarly, the top shelf and wall 213 havealigned openings (214 in FIG. 13) which form an upper tube sheet. In theembodiment of the invention illustrated in FIGS. 8-15, there areapproximately 49 copper tubes of approximate ¼-{fraction (3/8)} inchdiameter arranged vertically within the cooling chamber 217 between thetube sheets. The sizing and arrangement of the tube bundle creates aback pressure effect during operation which acts as a self-regulatingthermostat.

Water in the cold water sump 219 is refrigerated by the refrigerationcompressor 209 located in the top section of the design. Cold water fromthe cold water sump 219 is introduced into the evaporative coolingchamber through a distribution header 229. The distribution header inFIG. 9 is a series of PVC pipes which have downwardly directedperforations. The cold water which is sprayed downwardly from thedistribution header saturates an evaporative media which surrounds orotherwise contacts the riser tubes 227 in the cooling chamber 217. Theevaporative media is removed for ease of illustration in FIGS. 9 and 11but can comprise any of the media materials previously described withrespect to the first embodiment of the invention. Preferably, theevaporative media is supplied as generally rectangular pads which aresuspended from a rack (241 in FIG. 14) on the roof of the cooing chamberso that the pads are spaced between and separate the various verticalriser tubes 227.

Air is introduced into the cooling chamber by means of oppositelyarranged fans 231, 233. The fans 231, 233 are mounted on louvers (235,237 in FIG. 11) which can be manually adjusted to direct incoming andexhaust air from the cooling chamber 217 in a circular, vortex type flowpath which creates a turbulent air flow in the cooling chamber 217 andwhich enhances the evaporative cooling process. The vortex effectcreated by the side louvers 235, 237 causes air moving through thecooling chamber 217 to have an increased residence time within thecooling chamber. This increases the cooling effect and also preventswater droplets from being blow directly out of the shell plenum. Cooledair from the cooling chamber can be discharged through a suitable duct(such as duct 239 in FIG. 8) to the interior of the structure to becooled or can be discharged to the atmosphere.

Air is also being drawn into the intake plenum 221 by the intake fan225, which air flow is forced upwardly through the riser tubes 227located in the cooling chamber. The riser tubes pass though the coldwater sump and also contact the evaporative media in the coolingchamber, so that the outside of the tubes are cooled. The air within thetubes 227 is cooled by conduction through the tubes. This relativelydrier air can be directed through a suitable duct to the interior of thestructure to be cooled and can be combined with the cooled air from thecooling chamber, if desired.

In this latter embodiment of the invention, air is being cooled usingtwo simultaneous processes. Air is cooled by direct contact with waterin the evaporative cooling chamber 217, raising the absolute humidity ofthe air cooled in this manner. Additional air is also being cooled byconductive heat transfer within the riser tubes 227. The absolutehumidity of this additional air is either unchanged or only slightlychanged, or decreases slightly, due to condensation on the inside of theriser tubes. If desired, the two air flows can be combined into a singledischarge duct as described with respect to the first embodiment of theinvention, so that the discharged air consists of a mixture ofrelatively humid air from the evaporative process and air with nearambient humidity. Control over the humidity of the discharged air cantherefore be obtained by simply regulating the ratio of the twopreviously described air flows passing thru the exhaust duct.

The cold water sump (illustrated generally at 219 in FIG. 9) at thebottom of the cooling chamber serves as a cooling mass, as well as asump. The water in the sump is refrigerated to near freezing by means ofa commercially available, low temperature compressor similar to thatused on an ice machine and which can be AC or DC operated, but ispreferably operable on 12 Volt DC power. In the embodiment of theinvention illustrated in FIG. 11, the compressor 209 is batteryoperated. However, an associated inverter 243, located within theexhaust plenum area 251 allows the unit to be operated off AC currentto, for example, charge the batteries, during non-peak hours ofoperation. Locating the inverter within the chilled exhaust plenumcompartment prolongs its life since the operating temperature isreduced. The electric fans used in the intake plenum and on the coolingchamber are also preferably 12 Volt DC fans which can be driven by solarcells or storage batteries. FIGS. 10, 11 and 16, 16A and 16B illustratea particularly preferred refrigeration manifold 245 which is cooled bythe compressor 209 using traditional mechanical refrigerationtechniques. While a number of different traditional manifold or coilarrangements could be utilized with the compressor 209 to cool the waterin the sump 219, the preferred manifold 245 is especially efficient forthe intended application. As best seen in the isolated view of FIG. 16,the manifold 245 is a double stock manifold having a front layer 247 anda rear layer 249. The front and rear layers or coils are spaced apart bymeans of a plurality of cylindrical spacers 251. The cylindrical spacers251 are less wide than the total width of the manifold, leaving adistance “d” between adjacent spacers. The cylindrical spacers are alsohollow and open at both ends, allowing water in the sump 219 to flowaround and through the spacers. As shown in FIG. 11, the manifold 245 isarranged in a generally horizontal plane when in place in the sumpregion of the cooling chamber.

Refrigerant is supplied to and returned from the manifold layers by apair of “splits”, shown generally at 253 and 255 in FIG. 16. As shown inFIG. 16B, the top layer of coils is made up of loops 252, 254, 256, 258,260, 262, 264, and 266. (The loops are shown as broken-away halves forease of illustration.) The rear layer of loops is made up of loops 268,270, 272, 274, 276, 278, 280 and 282. The loop halves 252-266 form acontinuous coil on the front of the manifold. The loop halve 268-282similarly from a continuous loop on the rear of the manifold. The pointsat which the front and rear loops exit or terminate (generally 266,268in FIG. 16B) are connected by cross-over pipes 284, 286. The cross-overpipes 284, 286 intersect the first loop halves (252, 282, in FIG. 16B)to form the “splits 253, 255. The cross-over piping arrangement and thesplits 253 and 255 result in a type of “interlayered flow” through themanifold. For example, refrigerant passing through the split 253 flowsthrough branch 253B (FIG. 16) to the front layer 247 and through branch253A to the rear layer 249. Refrigerant returning from the front andrear layers 247, 249 meets at the split 255. The double stock manifoldwith its split flow operation nearly doubles the cooling capacity of thecompressor 209.

The following description is taken from an actual test run of the deviceillustrated in FIGS. 8-15, as described above. Without intending to belimiting, the following test results are intended to illustrate thefeatures of a particularly preferred embodiment of the invention. Thecase or housing sections of the device were formed of stainless steel.Two 12 volt fans, installed on opposite sides of the unit were used todraw outdoor atmospheric air into the main wet chamber, referred toherein as the “wet side” of the unit. Copper tubes extended through thewet chamber and a single 12 volt fan was used to force air through thetubes on what will be referred to as the “dry side” of the unit. The airsupply to the dry side came through a duct that extended into theconditioned space. The two airstreams (dry and wet side) were combinedinside the unit and directed to a single outlet. The unit incorporatedan integral mechanical refrigeration unit used to chill the water in thesump of the wet chamber. Batteries for 12 volt DC operation of the unitand an invertor were present to allow the operation of the unit from 120volt AC and for charging of the batteries.

Description of the Test Unit Installation:

The test unit was set up outside an enclosed automotive repair garage inBanning Calif. The air supply for the secondary (wet) side of the unitwas taken from the outdoor atmosphere. The garage was approximately 30′by 35′ with an approximate 14′ high ceiling. The combined outletairstream and the supply air to the primary (dry) sides of the unit wereducted through a door into the enclosed garage space. Both ducts wereapproximately 10′ long and straight with no turns. The duct for thecombined air outlet of the unit was 10.25″ I.D. (inside diameter) andthe duct for the primary (dry) side was 7.0″ I.D.

One door to the garage was left open to air for air to escape the garageand to eliminate any back pressure buildup in the garage space. For thefirst two tests, the unit was positioned only inches from the door. Forthe third test, the unit was moved back approximately 10′ from the doorbut the two ducts still extended through the door into the enclosedspace. For all three tests, the unit was located in the shade.

Test Data and Results Test # 1 For this test the unit was not pluggedinto AC power and ran off battery power. Outdoor ambient [alsosecondary(wet) inlet] 79.8° F., 19% RH, 480 cfm (Ft³/Min) Primary (dry)inlet condition 68.7° F., 28% RH, 10 cfm Combined air outlet 63.3° F.,42% RH, 490 cfm Air flow volume proportion 2% primary (dry) and 98%secondary (wet) Dry-bulb temperature drop across the unit. 16.3° F.(79.6 − 63.3) (used weighted average of primary and secondary air inletstreams) Theoretical maximum dry-bulb from 23.5° F. (79.6 − 56.1)psychrometric chart. Calculated humidifying efficiency. 69% (16.3 ÷ 23.5× 100) Sump water temperature 43° F. Test #2. For this test, the unitwas plugged into AC power and was run off of the invertor. Outdoorambient [also secondary (wet) inlet] 79.7° F., 17% RH, 532 cfm (Ft³/Min)Primary (dry) inlet condition 68.0 F, 30% RH, 10 cfm Combined air outlet63.3° F., 31% RH, 542 cfm Air flow volume proportion 2% primary (dry)and 98% secondary (wet) Dry-bulb temperature drop across the unit. 15.9°F. (79.5 − 63.6) (used weighted average of primary and secondary airinlet streams) Theoretical maximum dry-bulb from 24.1° F. (79.5 − 55.4)psychrometric chart. Calculated humidifying efficiency. 66% (15.9 ÷ 24.1× 100) Sump water temperature 45° F. Test # 3. Same as test #2 exceptthe unit was moved 10′ from door as described above. Outdoor ambient[also secondary (wet) inlet] 79.5° F., 18% RH, 532 cfm (Ft³/Min) Primary(dry) inlet condition 68.0° F., 30% RH, 10 cfm Combined air outlet 66.0°F., 32% RH, 542 cfm Air flow volume proportion 2% primary (dry) and 98%secondary (wet) Dry-bulb temperature drop across the unit. 13.3° F.(79.3 − 66.0) (used weighted average of primary and secondary air inletstreams) Theoretical maximum dry-bulb from 23.8° F. (79.5 − 55.4)psychrometric chart. Calculated humidifying efficiency. 56% (13.3 ÷ 23.8× 100) Sump water temperature 46° F.Note:For all three tests the Calculating humidifying efficiency is based onthe cfm weighted average dry bulb temperature and relative humidity % ofthe primary and secondary air inlet streams and the combined outputconditions.

As briefly mentioned above, the water within sump region 219 of thecooling chamber of the device is typically approximately 10 to 15degrees Fahrenheit cooler than the surrounding environment. Thisprovides the opportunity to provide some cooling to objects placed inheat exchange relationship with this water. For example, small objectscan be cooled without the expenditure of significant additional amountsof energy. Suitable containers can be placed directly in the water onthe shell side, or a cabinet accessible from the outside can be builtinto the shell side, or a stream of water circulated through, forexample, cooling coils external to the shell side, or the like. Asillustrated in FIG. 14, the water sump region of the cooling chamber canbe provided with one or more pairs of auxiliary refrigeration jacks 257,259 which can be plugged or capped if not in use. The auxiliary jackscomprise an inlet and outlet point for chilled water in the sump regionof the device. The chilled water can easily be pumped to another devicein the structure to be cooled, such as another heat exchanger, toprovide increased cooling.

FIG. 17 shows one such auxiliary refrigeration device 261. Theparticular device illustrated is approximately 15″ wide and 24″ high sothat it can conveniently be located between the studs of a wall in aresidential dwelling. Water from the sump 219 of the air conditioner 201is sucked through conduit 263 to the intake of a fluid pump 265. Pump265 discharges chilled water through conduit 267 to coil 269. A 12 voltDC fan 271 located behind a 12 by 12 inch coil forces air over the coiland is used to discharge cool air from the unit into the structure to becooled. The fan can be identical to the cooling chamber fans 231 and 233used on the main air conditioner unit. Return water is pulled throughconduit 273 back to the pump 265 and recirculated by the pump back tothe sump 219 of the main unit through the outlet conduit 275 to be onceagain chilled by the mechanical refrigeration system of the main unit. Acatch pan 274 can also be provided to catch any condensation. In oneembodiment of the invention, the inlet and outlet water conduits 263,275 are packaged into a “cable” arrangement (FIG. 18) having an outersheath of, for example a suitable polyolefin. The cable 277 could alsocontain a suitable shielded DC power supply line, illustrated as 279 inFIG. 18, for powering the fan 271 and pump 265.

Those skilled in the relevant arts will understand that various changesand modifications may be made in the preferred embodiments of theinvention described above. Typical cooling systems according to thepresent invention employ a heat exchanger with wet and dry sides thatare preferably substantially hermetically sealed from one another. Thewater supply system on the wet side of the heat exchanger is generallyprovided primarily to humidify the air on the wet side. As is wellunderstood by those skilled in the art with respect to conventionalevaporative coolers, the liquid water on the wet side is divided ordistributed by means of a spray or a wetted pad, or the like, so as toincrease the surface area of the water, and, thus, the rate ofevaporation of the water. Some chilling of the water on the wet sidealso necessarily occurs.

While the present invention has been described with reference tospecific embodiments wherein the shell side of a heat exchanger is thewet side and the tube side is the dry side, those skilled in the artwill readily appreciate from a consideration of these teachings thatother arrangements are possible, including, for example, the use of awet tube side and a dry shell side, or the like. Also, those skilled inthe art will be taught by the teachings herein that other forms of heatexchangers other than shell and tube can be employed, if desired.

What have been described are preferred embodiments in whichmodifications and changes may be made without departing from the spiritand scope of the accompanying claims. Many modifications and variationsof the present invention are possible in light of the above teachings.It is therefore to be understood that, within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallydescribed.

1. A cooling assembly comprising: a heat exchanger, said heat exchangerincluding a case member enclosing a wet side in heat exchangerelationship with a dry side, said sides being substantiallyhermetically sealed from one another; a first air moving member adaptedto move air through said dry side to produce a cooled stream of air; aliquid distributing member within said wet side; a liquid sump elementassociated with said wet side and adapted to receive liquid from saidwet side and to make said liquid available to said liquid distributingmember; at least two additional air moving members adapted to move airthrough said wet side from different locations to produce a humidifiedmass of turbulent air on said wet side; a mechanical refrigeration unitincluding a compressor and an associated refrigeration manifold, therefrigeration manifold being located within the liquid sump element forrefrigerating liquid contained therein; and an exhaust duct forconveying cooled air from the dry side of the assembly to the interiorof a structure to be cooled.
 2. The cooling assembly of claim 1,including an additional conduit which combines the cooled air from thedry side of the assembly with the turbulent air from the wet side anddelivers the resultant combined streams to the interior of a structure.3. The cooling assembly of claim 1, further comprising a DC power sourcefor powering the first and additional air moving members, the DC powersource including one or more storage batteries.
 4. The cooling assemblyof claim 3, further comprising an ambient energy harvesting systemoperatively associated with the storage batteries for charging thestorage batteries.
 5. The cooling assembly of claim 3, wherein the DCpower source supplies all of the power needs for the cooling assembly.6. The cooling assembly of claim 4, further comprising an electricalinverter which allows the storage batteries to be charged by an AC powersource.
 7. The cooling assembly of claim 4, wherein the ambient energyharvesting system includes at least one solar cell.
 8. A coolingassembly for cooling the interior of a structure, the assemblycomprising: a heat exchanger, said heat exchanger having a shell sideand a tube side; a first air moving member adapted to move air throughsaid tube side to produce a cooled, relatively dry stream of air; aliquid dispensing member on said shell side adapted to distribute liquidsubstantially throughout said shell side; a liquid sump elementassociated with said shell side and adapted to receive said liquid fromsaid shell side and to make said liquid available to said liquiddispensing member; a plurality of air moving members adapted to move airthrough said shell side from different directions to produce a turbulentmass of air on said shell side; a mechanical refrigeration unitincluding a compressor and an associated refrigeration manifold, therefrigeration manifold being located within the liquid sump element forrefrigerating liquid contained therein; and an exhaust duct forconveying cooled air from the dry side of the assembly to the interiorof a structure to be cooled.
 9. The cooling assembly of claim 8, whereinthe tube and shell side air moving members all require electrical powerfor their operation, the cooling assembly further comprising a batterysystem, the battery system being adapted to supplying all of therequired electrical power for operation of the assembly; and a solarcell system chargingly associated with the battery system.
 10. Thecooling assembly of claim 8, further comprising: a water supply systemassociated with the liquid sump and liquid dispensing member on theshell side of the assembly, the water supply system including a waterpump positioned between the liquid sump and the liquid dispensing memberfor maintaining the shell side of the assembly wet with water.
 11. Acooling assembly for cooling the interior of a structure, the coolingassembly comprising: a stacked chamber arrangement having a centrallylocated, forced-air evaporative cooling chamber which separates anexhaust air plenum located above the cooling chamber from an air intakeplenum located below the cooling chamber, the cooling chamber having atop wall and a bottom wall and surrounding sidewalls and a plurality ofvertically arranged riser tubes which connect the intake plenum with theexhaust air plenum, the bottom wall creating a cold water sump region;an intake fan, located within the air intake plenum, for drawing airupwardly through the plurality of vertical riser tubes which connect theintake plenum with the exhaust air plenum to thereby produce a cooledstream of air; a liquid distributing member located in the coolingchamber adjacent the top wall thereof; a pump for pumping water from thesump region of the cooling chamber to the liquid distributing member; apair of oppositely arranged fans mounted on the cooling chambersidewalls for moving air through the cooling chamber from differentlocations to produce a humidified mass of turbulent air within thecooling chamber; a mechanical refrigeration unit including a compressorand an associated refrigeration manifold, the refrigeration manifoldbeing located within the sump region of the cooling chamber forrefrigerating water contained therein; and an exhaust duct for conveyingcooled air from the exhaust plenum of the assembly to the interior of astructure to be cooled.
 12. The cooling assembly of claim 11, whereinthe oppositely arranged fans on the cooling chamber sidewalls aremounted over louvers, the louvers being adjustable to direct air in acircular vortex within the cooling chamber, thereby contributing to theturbulence of the air within the cooling chamber.
 13. The coolingassembly of claim 11, wherein the vertically arranged riser tubeslocated within the cooling chamber are copper tubes which are less thanabout ½ inch in diameter.
 14. The cooling assembly of claim 13, whereinthe vertically arranged riser tubes are in the range from about ¼ to{fraction (3/8)} inches in diameter.
 15. The cooling assembly of claim11, wherein the refrigeration manifold is a double stock manifold havinga front coil layer and a rear coil layer, the front and rear coil layersbeing spaced apart by means of a plurality of cylindrical spacers. 16.The cooling assembly of claim 15, wherein the cylindrical spacers areless wide than the total width of the manifold, leaving a distancebetween adjacent spacers, and wherein the cylindrical spacers are alsohollow and open at both ends, allowing water in the sump region to flowaround and through the spacers.
 17. The cooling assembly of claim 16,wherein the double manifold is arranged in a generally horizontal planewithin the sump region and wherein the front and rear coil layers of thedouble manifold contain a pair of flow path splits which act todistribute refrigerant which is communicated from the compressor to thecoils.
 18. A direct/indirect evaporative cooling assembly withrefrigerated chilled water sump for cooling the interior of a structure,the cooling assembly comprising: a stacked chamber arrangement having acentrally located, forced-air evaporative cooling chamber whichseparates an exhaust air plenum located above the cooling chamber froman air intake plenum located below the cooling chamber, the coolingchamber, intake plenum and exhaust plenum comprising a shell and tubeheat exchanger which encloses a wet side in heat exchange relationshipwith a dry side, the sides being substantially hermetically sealed fromone another; the cooling chamber having a top wall and a bottom wall andsurrounding sidewalls and a plurality of vertically arranged risertubes, the bottom wall creating a cold water sump region as well as thetop wall of the air intake plenum and a lower tubesheet for the risertubes, the top wall of the cooling chamber forming the bottom wall ofthe exhaust air plenum and an upper tubesheet for the riser tubes; anintake fan, located within the air intake plenum, for drawing airupwardly through the plurality of vertical riser tubes which connect theintake plenum with the exhaust air plenum to thereby produce a cooledstream of air from the dry side of the assembly; a liquid distributingmember located on the wet side of the cooling chamber adjacent the topwall thereof; a pump for pumping water from the sump region of thecooling chamber to the liquid distributing member; a pair of oppositelyarranged fans mounted on the cooling chamber sidewalls for moving airthrough the wet side from different locations to produce a humidifiedmass of turbulent air on the wet side; a mechanical refrigeration unitincluding a compressor and an associated refrigeration manifold, therefrigeration manifold being located within the sump region of thecooling chamber for refrigerating water contained therein; and anexhaust duct for conveying cooled air from the dry side of the assemblyto the interior of a structure to be cooled.
 19. The cooling assembly ofclaim 18, including an additional conduit which combines the cooled airfrom the dry side of the assembly with the turbulent air from the wetside and delivers the resultant combined streams to the interior of astructure.
 20. The cooling assembly of claim 18, further comprising a DCpower source for powering the intake and additionally arranged fans, theDC power source including one or more storage batteries.
 21. The coolingassembly of claim 20, further comprising an ambient energy harvestingsystem operatively associated with the storage batteries for chargingthe storage batteries.
 22. The cooling assembly of claim 20, wherein theDC power source supplies all of the power needs for the coolingassembly.
 23. The cooling assembly of claim 18, further comprising anelectrical inverter which allows the storage batteries to be charged byan AC power source.
 24. The cooling assembly of claim 21, wherein theambient energy harvesting system includes at least one solar cell. 25.The cooling assembly of claim 18, wherein the refrigeration compressoris a DC compressor which is located in a storage area on top of theexhaust plenum of the assembly.
 26. The cooling assembly of claim 18,wherein the liquid distributing member includes a distribution headerlocated in the cooling chamber adjacent the top wall thereof, andwherein the cooling chamber further includes pads of evaporative mediaarranged in the chamber between the vertical riser tubes to surround andcontact the tubes, whereby cold water is introduced from the sump regionof the cooling chamber and pumped through the distribution header ontothe evaporative media to thereby cool the riser tubes in the coolingchamber.
 27. The cooling assembly of claim 18, wherein the compressorand refrigeration manifold are operated to cool the water in the sumpregion to near freezing temperature.
 28. The cooling assembly of claim18, wherein an electrical inverter is located within the exhaust plenumof the assembly which allows the unit to be operated off AC current, thelocation of the inverter within the chilled exhaust plenum serving toprolong its useful life by lowering its operating temperature.
 29. Acooling assembly for cooling the interior of a structure, the coolingassembly comprising: a stacked chamber arrangement having a centrallylocated, forced-air evaporative cooling chamber which separates anexhaust air plenum located above the cooling chamber from an air intakeplenum located below the cooling chamber, the cooling chamber having atop wall and a bottom wall and surrounding sidewalls and a plurality ofvertically arranged riser tubes which connect the intake plenum with theexhaust air plenum, the bottom wall creating a cold water sump region;an intake fan, located within the air intake plenum, for drawing airupwardly through the plurality of vertical riser tubes which connect theintake plenum with the exhaust air plenum to thereby produce a cooledstream of air; a liquid distributing member located in the coolingchamber adjacent the top wall thereof; a pump for pumping water from thesump region of the cooling chamber to the liquid distributing member; anevaporative media located in the cooling chamber surrounding andcontacting the vertical riser tubes, the evaporative media being wet bywater pumped through the liquid distributing member; a pair ofoppositely arranged fans mounted on the cooling chamber sidewalls formoving air through the cooling chamber from different locations toproduce a humidified mass of turbulent air within the cooling chamber; amechanical refrigeration unit including a compressor and an associatedrefrigeration manifold, the refrigeration manifold being located withinthe sump region of the cooling chamber for refrigerating water containedtherein; an exhaust duct for conveying cooled air from the exhaustplenum of the assembly to the interior of a structure to be cooled;wherein the cooling chamber has a pair of auxiliary refrigeration jackswhich comprise an inlet and outlet point for chilled water in the sumpregion of the assembly; and wherein the auxiliary refrigeration jacksare connected by a suitable conduit to an auxiliary heat exchange devicelocated at a remote location within the structure to be cooled.
 30. Thecooling assembly of claim 29, wherein the auxiliary heat exchange deviceis a housing containing a fluid pump, a heat exchange coil and a fan,water from the cold water sump of the cooling assembly being pumpedthrough the coil and circulated back to the sump, the fan creating anexhaust air flow over the coil to provide additional cooling to thestructure.
 31. The cooling assembly of claim 30, wherein the pump andfan both operate off DC power, and wherein the conduit which connectsthe auxiliary heat exchange device to the cooling assembly also hasassociated therewith a power line for supplying DC current from the maincooling unit to the auxiliary heat exchange device.
 32. The coolingassembly of claim 31, wherein the inlet and outlet water conduits and DCpower line are all contained within a common sheath which is run fromthe main cooling assembly to the auxiliary heat exchange device.